Gear shifting mechanism



sept. 6, 193s.

P. MC CARTER ETAL 2,129,083

GEAR SHIFTING MECHANISM Filed June 1, 1936 Patented Sept. 6, 1938 @WWW arrasar cada smnrnte amcnainsin Philip Carter, White Plains, N., il., and lllbonglas li. lirinsiey, Nortvailr, Conn., assignent to Waco llrodncts, line., ilersey ity, hl., it, a corporation ot llllelaware Application .tiene i, iiitd, Seriali No. difatti@ d Claims.

The present invention relates to duid pressure motors and more particularly to a novel and improved suction operated motor for the shitting of the transmission gears of an automobile trans- 5 mission.

Objects and advantages of the invention will be set forth in part hereinafter and in part-will be obvious herefrom, or may be learned by practice with the invention, the same heing realized lo and attained by means of the instrumentallties and combinations pointed out in the appended claims.

The invention consists in the novel parts, construction, arrangements, combinations and irn- .5 provements herein shown and described.

The accompanying drawing, referred to herein and constituting a part hereof, illustrates one f embodiment of the invention, and 'together with the description, serves to explain the principles :o of the invention.

The single ligure of the `drawing is a diagrammatic representation of a fluid pressure operated motor and its controlling valve, as constructed in accordance with the present invention, many oi' :5 the parts being shown in section and certain other parts being broken away.

Thepresent invention has for its object the provision of a uid pressure operated motor having control means for varying the speed oi travel of a piston or other moving element during certain portions of its travel. Another object oi the invention is the provision of a suction operated cylinder and piston provided with means for slowing the piston during an intermediate portion of its travel in the cylinder. Still another object of the invention is the provision of a novel and improved suction operated motor for the shifting of the transmission gears of a, selective sliding gear transmission of the synchro- 0 mesh type in which synchronizing clutches are provided to prevent clashing of the gears as they are slid into mesh.

In fluid pressure operated gear shifting devices of the type heretofore generally known, the piston 5 connected for shifting the gears moves at substantially a uniform speed throughout its stroke, with the result that when this type of motor is used for shifting the gears of a synchro-mesh transmission from a higher to a lower speed (a lower to a higher gear ratio) either the synchronizing clutch is overloaded, the shifting operation as a whole must be slowed down to a point where it is sluggish, or the gears clash and thus defeat one of the principal objects of the synchro-mesh transmission.

im., liti-@titl fin accordance with the present invention, and where suction is used as the actuating torce, inll suction is ilrst applied to one side of the piston move the gears or their positive clutches ont ci? meshed position, and the iullsuction is continned until the shifting member is approximately neutral position. in this position, the suction is interrupted and is thereupon applied to a suctionoperated valve through a restricted duct and aiter a short interval oi time, this valve is opened la so as to ire-apply the full suction to the piston. During the moment of interrupted suction, the gears are synchronised, as this interruption corresponds in position to the synchroninlng position of the sluiting member, and in the lllmtrated in embodiment, the interruption is controlled by the position of the piston which is connected to the shifting member. Means are also provided ier variably restricting the duct leading to the suction-operated valve so that the'period oi' delay 2o may be varied d pending upon the maximum Spee-nett which it ls desired to shift gears.

ln general, the control means oi the present invention need be applied only to the intermediate speed of a, three-speed transmission, as there is a relatively small duty on the synchronizing clutches when shitting from intermediate to third speed, and it is only seldom desired to shift from intermediate to low speed. This arrangement thus serves to control the shift from nrst or third to intermediate speed.

It will be understood' that the foregoing general description and the following detailed description as well, are exemplary and explanatory of the invention but are not restrictive thereof.

Referring now in detail to the illustrative embodiment of the invention, as shown in the accompanying drawing, the fluid pressure operated motor is in many respects similar to that shown in the prior patent to Douglas l5'. Linsley, No. 40 1,733,502 and comprises a double-ended cylinder l@ having end walls il and l2 mounted rigidly with respect to the transmission casing li. Within the cylinder is a piston le connected to a pis- 5 ton rod it passing through air-tight guides it' and il in the 'end walls ll and i2 of the cylinder. At one end the piston rod is slotted, as at til, to receive the rounded end 2i of a pivoted lever 22 having its other end 23 connected to the 50 gear shifting rod 2t for the second and third speed gears (not shown) ln a conventional manner. By moving the piston forwardly, the gear shifting fork is moved rearwardly to shift the gears into second speed position while by moving the piston rearwardly the gears are shifted into high or third speed position.

A selector valve 30 of conventional construction is provided for selectively applying suction to the third speed duct 3l, neutral duct 32, or second speed duct 33 by sliding the valve slide 35 to one or the other of its positions, and thev application of suction to any one of these ducts causes movement of the piston I4 and lever 22 to the corresponding position.

As shown in the prior Patent No. 1,733,502, means are provided for selectively admitting air to one or the other end of the cylinder I as suction is applied to the opposite end, and these means comprise theA automatic valve 40 mounted on the cylinder end wall I2 and controlling the admission of air through ducts 4I or 42 by the application of suction through these ducts. That is, when suction is applied to duct 3| to move the piston to third speed position,'air is admitted through the duct 42 by the operation of these automatic valves, thereby allowing a greater pressure difference to be established between the two sides of the piston I4 than would otherwise be the case.

For controlling and varying the speed of travel of the piston I4 from its third speed to its second speed position, and for causing it to be slowed as it passes the synchronizing point, duct 33 is branched intermediate itsends, as at 33a and 33h, and in branch 33a is provided a valve 45 having a plunger 46 adapted to contact with the second speed end of piston rod I5. Plunger 46 is formed with a reduced portion 41 serving as a valve duct to open or close the branch 33a, and a spring 48 is provided for normally holding plunger 46 in valve opened position, as shown in the drawing. For varying the operation of the device, the end of plunger 46 may be provided with a threaded cap 46' so that the engagement of the parts I and 46 may be varied to change the position at which the piston i6 is checked.

T.n the other branch 33h is provided a suction operated valve 50 comprising a valve plunger 5I vhaving a reduced portion 52, and this plunger is normally held in closed position by spring 53, but may be moved to open position by the application of suction to one end of the plunger 5i through duct 55. Duct 55 is connected to branch 33a. through valve 45 which is provided with ports 58 and 59. Port 58 is normally closed by the end of plunger i6 while the same end of the plunger is cut away so that port 59 is normally open to atmosphere through the vent 66 at the end of valve 45. `Means are also provided for variably restricting the duct 55, and for this purpose a'needle valve 62 is provided in the end of valve 50 so as to restrict the flow of air from the end of plunger 5I.

With the parts as shown in the iigure of the drawing, the plunger 46 is engaged by the forward end of piston rod i6 as the piston passes neutral in moving towards second speed position.

In the operation of the illustrative embodiment, and assuming that the gears are to be shifted to second speed position, by movement of the piston from either high speed or neutral position under the suction as applied through pipes 33, 33a and valve 4l, the end of the piston rod I5 engages plunger 46 and on continuing the application of suction through duct 33 and branch 33a to the forward end of cylinder I0, the plunger 46 is moved to shut oi branch 33a, thereby interrupting the application oi' suction to the forward end of cylinder I0 and thereby checking or stopping the movement of piston I5 at the synchronizing point.

As branch 33a is closed, duct 41 opens port 56 to port 59, thereby allowing suction to be applied through duct 55 and the controllable restricting valve 62 to the end of plunger 5I. and again applying suction to the forward end of piston I4 so that its rapid movement is resumed.

This manner of operation assures that the piston I4 moves rapidly up to its neutral position and to the position indicated by the Adot and dash lines S, at which point the synchronizing clutches in the transmission are engaged and synchronization of the gears is started. At this point the application of suction is discontinued momentarily, allowing a suflicient and controlled interval for complete synchronization of the' gears, the length of this interval being determined by the smallness of the restricting valve 62.

By adjusting the restricting valve 62 to a larger opening, the synchronizing interval may be reduced, thereby allowing the gears to crash if the shifting operation is attempted at too high a speed with a resultant warning to the driver that he is unduly burdening the synchronizers of the transmission. The operation of valve 45 may be timed by the threaded cap 46 of plunger 46, thus adapting the point of synchronism of the device to the requirements of the particular transmission and driver.

The invention in its broader aspects is not limited to the specific mechanism shown and described but departures may be made therefrom within the scope of the accompanyingl claims without departing from the principles of the invention and without sacriiicing its chief advantages.

l. In a suction operated motor, the combination of a cylinder and a piston, a suction duct having two valves in parallel therein and connected to one end of the cylinder, means for operating one of the valves by suction and the other valve being alternatively openable to the cylinder or first valve to operate it by suction and means for operating said other valve by the piston.'

2. In a suction operated motor, the combination of a cylinder and a piston, a suction duct having two valves in parallel therein and connected to one end of the cylinder, means for operating one of the valves by suction and the other valve being operated by the piston, a passage controlled by the piston operated valve through which suction may be applied to operate the suction valve whereby the suction applied to the cyly inder is rst cui; off and is then restored through sequential operation of the valve means.

3. In a suction operated motor, the combination of a cylinder and a piston, a suction duct having two valves in parallel `therein and connected to one end of the cylinder, means for operating one of the valves by suction and the other valve being operated by the piston, a passage controlled by the piston operated valve through which suction may be applied to operate the suction valve, means normally holding said suction operated valve closed, and means normally holding the piston operated valve open to the cylinder whereby suction is rst applied to the cylinder, is momentarily interrupted and applied to the suction operated valve to open it and restore suction to the cylinder.

4. In a suction operated motor, the combination of a cylinder and a piston, a suction duct having two valves in parallel therein and connected to one end of the cylinder, means i'or ope. ating one of the valves by suction and the other valve being alternatively openable to the cylinder or iirst valve, means for operating said. other valve by the piston, and means for varying the relation of the piston and other valve.

5. In a suction operated motor, the combination of a cylinder and a piston, a suction duct having two valves in parallel therein and connected to one end of the cylinder, means for operating one of the valves by suction and the other valve being operated by the piston, a passage controlled by the piston operated valve through which suction may be applied to operate the suclftion valve, means normally holding said suction operated valve closed, means normally holding the piston operated valve open' to the cylinder whereby suction is first applied to the cylinder, is momentarily interrupted and applied to the suction operated valve to open it and restore suction to the cylinder', and means for varying the relation of the piston and other valve.

6. In a uid pressure operated gear shifter having a cylinder and piston and a selector valve controlling the application of fluid pressure to the cylinder, said piston being connected for moving the shifter fork of a synchrom'esh transmission, the combination of an air duct having two valves in parallel and in series with the selector valve'A and connected to one end of the cylinder, means for operating one of the two valves by the piston and means for operating the'other of the two valves by fluid pressure controlled by the first of the two valves. f

7. In a fluid pressure operated gear shifter having a cylinder and piston and a selector valve controlling the application of iiuid pressure to the cylinder, said piston being connected for movingthe shifter fork oi' a synchromesh transmission, the combination of an air duct having two valves in parallel and in series with a selector valve and connected to one end of the cylinder, a passageway from one of the two valves to the other, means for operating one of the valves by iiuid pressure applied through the passageway and other valve and means for operating the' other of said two valves by the piston rod.

8. In a suction operated gear shifter having a cylinder and piston and a selector valve controlling the application of suction to the cylinder, said piston being connected for moving the shifter fork of a synchromesh transmission, the combination of an air duct having two valves in parallel and in series with a selector valve and connected to one end of the cylinder, a passageway from one of the two valves to the other, means for operating one of the valves by suction applied through the passageway and other valve and means for operating the other of said two valves by the piston rod.

9. In a iiuid pressure operated gear shifter having a cylinder and piston and a selector valve controlling the application of fluid pressure lto the cylinder, said piston being connected for moving the shifter fork of a synchrome'sh transmission, the combination of an air duct having two valves in parallel and in series with a selector valve and connected to one end of the cylinder, a regulably restricted passageway from one of the two valves to the other, means for operating one of the valves by uid pressure applied through the passageway and other valve, means for operating the other of said two valves by the piston rod, and

means for varying the relation of the other valve and piston.

PHILIP M. CARTER. DOUGLAS F. LINSLEY. 

